Hanks revealed his status on Twitter and said the couple are in Australia and fell ill.
In his Tweet, he said they were tested after the two felt tired, had colds and body aches.
Hanks said medical officials there have protocols that must be followed, and he and Rita will be tested, observed and isolated for as long as it's required.
Wednesday evening, Colin Hanks released a statement thanking fans for the outpouring of support and saying his parents are in good spirits.